(m-1)(2m-1)-(m+1)2+1=2m2-m-2m+1-(m2+2m+1)+1=2m2-m-2m+1-m2-2m-1+1=m2-5m+1,∵m2-5m-14=0,∴m2-5m=14,∴原式=(m2-5m)+1=14+1=15.